The present invention is directed at a method and apparatus for producing bags preferably from a roll film source and preferably for use in producing foam cushion bags.
In the packaging industry, a variety of devices have been developed to automatically fabricate foam filled bags for use as protective inserts in packages. Some examples of these foam-in-bag fabrication devices can be seen in U.S. Pat. Nos. 5,376,219; 4,854,109; 4,983,007; 5,139,151; 5,575,435; 5,679,208; and 5,727,370.
In addition to the common occurrence of foam dispenser system lock up or poor mix performance in prior art foam-in-bag systems, the film supply, tracking, sealing and feed components of prior art foam-in-bag systems also represent particular sources of headaches for operates of prior art devices. The headaches include, for example, attempting to understand and operate a highly complicated, multiple component assembly for feeding, sealing, tracking and/or supplying film (often C-fold) to the bag formation area; high breakdown or misadjustment occurrence due to the number of components and complex arrangement of the components; high service requirements (also due in part to the number of components and high complexity of the arrangement in the components); poor quality bag formation, often associated with poor tracking performance, particularly with respect to C-fold film supply systems which have a different type of side edge arrangement (unconnected versus connected edge) that is inherently prone to difficult maintenance of good tracking characteristics; vent hole blockage and/or product contamination from foam exiting the vent(s); and lack of versatility in regard to vent length and vent location.
Another particularly problematic area associated with the prior art foam-in-bag system lies in the area of heated resistance wire replacement, both in regard to edge sealing and in regard to the cross-cutting sealing systems. In the prior art systems, there is often required delicate operator manipulation with certain tools to achieve removal and reinsertion of broken, or worn, heated wires (which is a common occurrence in the thin heated resistance wires used in the industry to form the seals).
In addition, prior art systems suffer from other drawbacks, such as relatively slow bag formation and a slow throughput of completed bags which, in some systems, is partially due to a reverse feed requirement to break an upper, no-yet-completely formed bag from a completed bag with one or both adhered by the bond formed between the earlier melted and presently cooled plastic material on the heated cross-cut wire.
The present invention is directed at providing a bag forming assembly which helps to avoid or lessen the effect of the numerous drawbacks associated with the prior art systems such as those described above. In so doing, the present invention presents a highly versatile machine that provides numerous advantageous features without invoking added complexity and added components, which is a common tendency in the prior art systems, particularly of late. These advantageous features of the present invention include, for example:
a) the formation of bags through use of a single supply roll source which is a two-ply supply roll containing a two layer supply of rolled independent sheets;
b) a dual function motor that acts to drive the drive roller of the present invention and, at the desired point in time, also drives a pivoting cross-cut bar to a cross-cut formation location from a standby location and vice versa, to avoid the requirement for a secondary activation system for forming the cross-cut and the added complexity associated therewith;
c) an automatic bag/cross-cut wire separation feature which avoids the common prior art requirement of providing a reverse feed movement in the bag film supply;
d) biased edge seal inserts which apply constant pressure against the side edges of roll film material being passed between the edge sealers and drive roller of the present invention for facilitating constant contact and for creating a drag effect which provides a self-cleaning function as tube film is dragged past the heated wire component of the heating unit;
e) an easily removable and installable pair of edge seal inserts for easy edge seal heat wire maintenance and which have a reduced electrical current/power source demand, and in a preferred embodiment, feature plug-in cartridge heat units for even easier edge seal heat wire maintenance;
f) a continuous and uninterrupted edge seal arrangement which is preferably adjustable with the driven roller and provides a non-leak seal for the full longitudinal length of the bag and preferably along both sides;
g) a vent former that is also preferably supported by the driven roller and preferably includes a heat cutter positioned inward of the permanent edge sealer and circumferentially above the edge sealer heat unit (and thus above the nip) so that the heat cutter cuts a vent in only one of the two plies such that foam contamination of packaged products can be avoided through strategic positioning as to which side of the bag faces the container and which side faces the product;
h) a vent former arrangement which allows for easily varied vent lengths, longitudinal vent positioning to suit specific packaging requirements, the option of forming a vent only on one side or on both sides, vent formation in only one face of a formed bag (a feature that provides advantageous versatility in contamination avoidance) and the ability to avoid edge fold over vent blockage, and the avoidance of seal breaks due to an inward positioning of the vent hole with respect to a continuous side edge seal;
i) a driven wheel/edge seal insert/vent former combination which is easily laterally adjustable together so as to achieve a desired opposite edge seal spacing and vent formation positioning for a variety of bag width sizes;
j) a downstream xe2x80x9cpull downxe2x80x9d feed system which avoids the complication of attaching a driver to the roll supply (typically an inserted roll core driver) and providing an active braking system, and which can utilize merely an inactive friction enhancement system in an upstream support roller;
k) a knurled driven roller pair which, together with a compression relationship with the drive roller, helps maintain a non-slip tension in the two-ply film stack being pulled down through the system;
l) a rapid bag formation and bag throughput system which is particularly advantageous for use with a high throughput foam dispenser system, to provide not only an increase in foam-in-bag formation production, but the ability to provide improved foam expansion efficiency (i.e., more ft3. in foam per lb. of chemical due to the avoidance of pouring new foam mix onto earlier poured and beginning to expand foam mix) as well as the benefit of being able to insert bags into an area of use before the foam-in-bag significantly converts from its cream state to a rapid rise state;
m) a control system that provides, partly in conjunction with the dual purpose single motor feature of the present invention, a highly efficient and easily manipulated roll-film bagger (e.g., bag length characteristics coordinated with the foam input timing and vent positioning and length options);
n) an easily serviceable cross-cut heated wire system which avoids inefficient service down time in a manufacture cycle as it provides an order of magnitude difference in cross-cut change time;
o) a significant lessening of the number of overall components due in part not only to the dual function motor described above, but also to other features such as the use of the drive roller itself as a back support means for the film supply being pinched by the cross-cut bar during the cross-cut/seal step of the present invention;
p) a compact system which is due in part to the lessening of components discussed above, placement of the dual function drive motor and one-way clutch within the interior of the drive roller, and the avoidance of a requirement for a tracking system above the roller and/or the requirement for an active-tensioning system and/or the requirement for an active film braking and feed system at the roll supply location;
These and other advantageous features of the present invention will become more apparent following a review of the summary discussion below describing the preferred embodiments of the present invention and the detailed discussion that follows.
The present invention features a bag forming apparatus that includes a film drive assembly which comprises a driver and a film drive wheel that is driven by said driver; a film cross-cut device; and a drive transmission system which interconnects said film cross-cut device to said driver such that said driver is adapted to both drive the drive roller and drive said film cross-cut device. The cross-cut device is supported by said drive transmission system such that said driver moves said cross-cut device into a pinch relationship with said drive roller wherein film fed by said drive roller is pinched between said cross-cut device and said drive roller to facilitate cross-cut formation. Preferably, the driver is a motor received within an internal cavity of said drive roller.
A support framework supports said drive roller and said drive transmission system, and said drive transmission system includes a motor mount that is connected with said motor and pivotally received by said support framework and a cross-cut device support assembly that includes a pivot support member pivotally received by said support framework and an interconnector extending between said pivot support member and cross-cut device. The drive transmission system further comprises a sub-drive transmission system which places said motor mount in driving communication with said pivot support member such that rotation in said motor mount causes rotation in said pivot support member, interconnector and connected cross-cut device. In this way, the pivot support member, interconnector and cross-cut bar are positioned with respect to said drive roller such that upon rotation of said motor mount in a first rotation direction said cross-cut bar swings from a stand-by position into a pinching relationship with respect to said drive roller such that film material fed by said film drive roller is pinched between said cross-cut device and said drive roller to facilitate cross-cut formation in the film material. However, upon a reverse rotation of said motor mount in a second rotation direction, said cross-cut bar rotates from the pinching relationship to said stand-by state, and the angle of rotation between an uninterrupted film feed supply plane and the stand-by state is greater than the angle of rotation between said feed supply plane and the pinching relationship such that automatic film separation is facilitated. The cross-cut device preferably includes a heated wire cross-cut former (and sealer) which is supported by a cross-cut bar and has a length essentially equal to or less than that of said drive roller along the drive roller axis of rotation with the wire suspended above a groove formed in an elongated cross-cut bar and within which groove a heat dissipating pad is preferably positioned. The cross-cut wire is bent around end wheels supported by the cross-cut bar and held by a fastener extending into the back of the bar. Thus, the film drive assembly preferably includes an elongated drive roller which is dimensioned to contact an intermediate portion and side portions of film material being fed by said drive roller and provides the back support component for the pinching operation of the cross-cut device.
The bag forming apparatus also preferably comprises a pair of driven rollers and a driven roller support rod which places said driven rollers in a compression relationship with respect to film fed by said drive roller, and said driven rollers being pivotally supported by said support rod and also in sliding friction contact with said support rod so as to facilitate film width adjustments in said driven rollers along a length of said support rod. The support rod is also connected to said cross-cut device and rotatable by said drive transmission system without invoking rotation in said driven rollers when said driven rollers are in said compression relationship with respect to said drive roller and film fed by said drive roller. The preferred embodiment of the present invention is directed at foam-in-bag type bag formation from a two-ply supply roll of film material, although other bag types can also be utilized (e.g., a tube film supply) with the appropriate modifications to the highly versatile system of the present invention. The present invention preferably features a first edge sealer and a first of said pair of driven rollers includes an intermediate slot for reception of said edge sealer. In a more preferred embodiment, the bag forming apparatus further comprises a second edge sealer received within a slot formed in a second of said pair of driven rollers. Also, each edge sealer preferably has biasing and engagement means for engaging the pair of driven rollers so as to be biased outward from said driven roller and toward said drive roller in floating fashion.
In an alternate embodiment of the present invention each driven roller is designed to support two card-like inserts with an outer one having means for forming a continuous edge seal and an inner card having means for forming a vent inward of the edge seal. The inward positioned vent hole former is preferably a heat unit cutter or (less preferably) a blade or sharp edge cutter and is preferably positioned a few inches inward of the continuous, permanent edge seal. The vent hole former, in addition to being inward of the edge sealer, also has an upstream contact location such that the heat cutter only comes in contact with a single sheet of the film material before that single sheet reaches the drive roller nip location. Thus, with this arrangement a vent hole is formed only on one side of the bag such that foam contamination of a product can be avoided by positioning the vent so as to face the package or container and not the product being protected.
Also, through use of an appropriate operator interface with the controller, an operator can adjust the longitudinal length of the vent hole based on the duration of heating time in the vent hole former and also the location of the vent hole with respect to the longitudinal length of the bag by choosing the heat on and heat off points between the bag""s upper cross-cut seal and lower cross-cut seal""s location. Thus, a series of vent holes can be formed, if desired, along the longitudinal length of the bag of a variety of lengths through appropriate vent starting points and heat duration control. Further, under the unique venting system arrangement of the present invention, an operator can easily set the vent hole forming system so that only one side is effected by the vent hole former, while the other side is not vented. This also increases the versatility in the matching of the appropriate vent configuration in the bag with respect to the product being protected. Alternatively, under the versatile design of the present invention, one vent former insert can be replaced by a secondary edge sealer card, such that an additional longitudinal seal can be formed inward of the outer edge seal along at least one side of the bag (possibly both if an alternate top-center vent formation design or a third insert arrangement is utilized as discussed below).
Rather than two separate inserts for the edge sealer and vent former, the present invention also features a single dual function insert wherein the insert""s single main body supports body an edge sealing forming means (e.g., an edge sealer plug-in heat unit) at a nip level and a vent forming means (e.g., a second plug-in heat unit or cutter blade) positioned at a location on the main body that is above the edge sealer forming means. Although the vent forming means is preferably positioned inward of the edge sealer forming means (e.g., {fraction (1/16)} to xc2xc inch) in this common support embodiment, in an alternate, less preferable, embodiment the vent former and edge sealer heat units can be placed along a common vertical plane (and preferably along a common arc of a curved face of the main body support), as despite the continuous and uninterrupted operation of the edge sealer, the vent hole forming means forms a vent hole that typically is large enough as to not be sealed by the downstream continuously running edge sealer. From the standpoint of avoiding the possibility of vent hole blockage due to edge curl over during packaging, the more inward, separate insert arrangement is more preferable; although it involves another insert card on each driver roller.
In a preferred embodiment, the film drive roller represents the only film driving means of said bag forming apparatus. Thus, the single, elongated cylindrical drive roller pulls the film material from its supply source toward it and past it. Because the drive roller represents the only driving force on the film, the supply film source can be a roll of film that is merely placed on the bag forming apparatus loosely and without active braking or a roll rotation feed means. The bag forming apparatus of the present invention also preferably comprises a one-way rotation device that is arranged so as to allow rotation of said drive roller in a film drive direction and to prevent rotation of said drive roller in a non-film drive direction. The driver includes a reversible motor, a drive shaft and a motor housing, and said motor, drive shaft and motor housing are arranged such that, upon reversing said motor to rotate said drive shaft in a non-film drive direction, the blockage of rotation of said drive roller by said one-way rotation device leads to rotation blockage in said drive shaft and rotation of said motor housing to initiate a driving of said cross-cut device. The drive transmission system includes a rotatable cross-cut support rod that extends adjacent said drive roller and a cross-cut connector that connects the cross-cut device to said cross-cut support rod such that, upon rotation of said cross-cut support rod by said drive transmission system, said cross-cut device is swung upward and into a film pinching relationship with said drive roller. Preferably, the drive roller includes a compressible outer layer supported by a less compressible inner roller unit, with the outer layer being high heat resistant and capable of rapid heat dissipation with silicone being suitable. Preferably, the drive assembly, drive transmission, and driven support rod are interconnected such that, upon a switch in said reversible roller from a non-film drive rotation direction back to a film drive rotation direction, said cross-cut bar is first swung back from the pinching relationship to a stand-by state prior to a driving of the film roller.
The aforementioned support for the roll of supply film preferably comprises a single roll supply support assembly having two rotatable support rollers arranged for direct contact with a single supply roll of film material and a passive braking device for preventing inertia induced over rotation of said support rollers when said drive roller discontinues pulling on film material from said supply roll. The passive braking device can include a loop of friction material extending about one of said rotatable support rollers and having an extension which facilitates non-rotation of said loop with said roller. An example of such an extension includes a second loop of friction material extending around a second of said rotatable support rollers. The first and second single supply roll support rollers are spaced close enough together to receive and hold thereabove the single roll of film material despite more than at least a majority of the film having been fed from the roll. As noted, the rotatable support rollers preferably represent the sole points of contact of said bag forming apparatus with the supply roll, and there is not a requirement for confinement means along the axial direction of the supply roll.
In a preferred embodiment, the single roll is a single roll of two ply film material (i.e., each side edge not connected). With such a supply, the bag forming apparatus includes a first ply path forming member positioned below a first of said single roll support rollers and a second ply path forming member positioned below a second of said single roll support rollers with said first ply path forming member being positioned to facilitate the feeding of a first ply from the single supply roll, which is a two ply single roll of film material, from a first contact location with said first roll support roller, outwardly past said first supply member and into a nip location formed between said drive roller and said driven rollers, and said second ply path forming member is positioned to facilitate the feeding of a second ply from the supply roll from a first contact location with said second roll support roller, outwardly past said second ply feed member and into the nip location formed between said driven and drive rollers. Thus, in one embodiment of the invention, a bag forming apparatus is provided that comprises a single two ply film material supply roll and a support assembly for supporting said single supply roll such that each ply of said two ply film material is feedable into driving contact with said drive roller from opposite, external front and back sides of a support framework.
A preferred interrelationship for one embodiment of the present invention features a bag forming apparatus that has a film material drive roller with a continuous widthwise film material contact surface featuring an intermediate portion positioned between two side edge portions. The intermediate portion of the drive roller is designed for contact with an intermediate portion of film material to be fed by said drive roller and the two side edge portions of said drive roller are designed for contact with respective edge portions of the film material to be fed by said drive roller. Thus, the pair of driven rollers are positioned so as to be driven by said drive roller together with the feeding of the film material by said drive roller, and said pair of driven rollers are spaced apart along the length of said drive roller so as to provide a bag fill clearance area or space therebetween providing a suitable location for receiving a foam mix whether the dispenser directs it straight down into a cross-cut seal formed by a cross-cut device either in common with a vertical plane that passes through the nip or more preferably an offset arrangement which is within a range of an inch or so from that plane toward the driven roller side. The outlet of the dispenser can also be tilted at an angle (e.g.,  less than 10xc2x0) either to the left or right along the cross-cut wire seal direction or in a transverse front to back relationship, although a vertical angle (no tilt angle) with xe2x85x9 to xc2xc inch offset toward the driven side arrangement is preferred. The cross-cut device is driven by a cross-cut device position adjustment assembly which drives said cross-cut device into and out of contact with film material that is in a feed relationship with respect to said drive and driven rollers for forming a cross-cut in the film material in the feed relationship.
At least one of said drive roller and driven rollers includes a compressible material outer layer and said driven and drive rollers are in a compression relationship while in a film material driving mode, and, preferably, at least one of said drive and driven rollers is of less compressible material than the drive or driven roller having the compressible material outer layer. The driven rollers are slideably adjustable along said support rod arrangement to accommodate different bag width formation modes. The support rod supporting said cross-cut device operates such that said cross-cut device is pivoted about an arc between a standby state removed from said drive roller and a cross-cut formation state wherein said cross-cut device is in a film material pinching relationship with said drive roller.
The present invention is also directed at a pair of edge seal members releasably supported on said driven rollers and adjustable in relative spacing with said driven rollers. The edge seal members have a recessed hook section which frictionally engages a reception component of said driven rollers with said friction engagement represents a sole means of engagement of said edge seal members with respect to said driven rollers such that hand removal and insertion of the edge seal members is easily achieved.
In one preferred embodiment of the present invention, the bag forming apparatus is a foam-in-bag type bag forming apparatus. Thus, in this embodiment, the support framework supports a foam mix dispenser and a foam mix dispenser device support assembly. Preferably, said support framework includes a first passage opening formed in a first side wall thereof which passageway is dimensioned larger than said dispenser to allow for insertion and removal of said dispenser and dispenser support assembly, and said dispenser device support assembly includes a cover plate and support framework engaging means for non-tool disengagement of said dispenser support assembly from said support framework. The support framework also features a second side wall having a second passageway formed therein which is similar to the first passageway at least insofar as being able to receive said dispenser.
Also preferred embodiments of the film edge sealer and below described vent former feature a main body that has a capture recess formed therein which is dimensioned for frictional attachment to a support component of a bag film support assembly positioned adjacent film material being fed therepast during operation. The edge sealer and vent former further each comprise a heating unit supported by said insert main body, and the main body has a thin, card-like configuration and the heating unit is formed along a relatively short extension of an exposed peripheral side edge of said main body.
In the edge sealer, the heating unit is positioned so as to contact the stacked film material at the nip location or sufficiently close enough thereto to band the two sheets of film material together. The vent former has a different positioned heating element as compared with the edge sealer as it is positioned on the peripheral side edge of the supporting main body further up and backward along the curved front face of the main body. This positioning of the vent former heat unit (or blade) ensures that only one of the film material sheets is effected as it comes in contact with only a single sheet prior to two sheets sufficiently merging near the nip location into a position that could undesirably melt or slice the second sheet. The present invention can feature an arrangement wherein both films are effected by the vent former, but this results in a loss of the numerous advantages described herein such as being able to form a vent in only one side of the bag. The heating unit is preferably a plug-in unit similar to an automobile plug-in fuse or of another design such as an extension of a heating wire that extends from an outlet opening in said exposed peripheral edge, and returns through an inlet opening in said exposed peripheral edge spaced less than an inch from said outlet opening. Also, the main body""s capture recess includes a biasing device therein, wherein said biasing device is preferably a lever extension of said main body having an interior edge positioned for contact with the support component and an exterior edge separated from a remaining portion of said main body. The interior edge also preferably includes a concavity opposed to another concavity on an opposite wall of the capture recess with the facing concavities designed to engage a cylindrical, internal bar section of a driven roller and cause the lever to deflect outward and to have a floating function. The aforementioned plug-in heating unit preferably features a cartridge that has a plug-in base designed for plug-in reception by the reception opening of said main body and a heating unit supported by said base.
A preferred embodiment of the present invention is a particular compact design partly due to the drive roller unit utilized which has an elongated main body having a first cavity for receipt of a motor therein. The first cavity is formed at one end of said main body and said main body includes a second cavity at an opposite end of the drive roller and which receives a one-way rotation mechanism.
The present invention is also directed at a method of forming a bag which comprises feeding a first ply of a two-ply single roll of film along a first path to a film feed mechanism; feeding a second ply of the two-ply single roll of film along a second path and into contact with said first ply at said film feed mechanism; forming opposite edge seals in the first and second ply of material; and forming a cross-cut seal in the first and second ply of material. In a preferred method, the bag being formed is filled with foam and thus said method further comprises feeding a foam mix to said bag by injecting foam into a location above the cross-cut seal and prior to complete formation of side edge seals in the bag currently being supplied with foam mix. The method of the present invention further includes the formation of a cross-cut seal which involves bring a cross-cut device into a pinching relationship wherein said first ply and said second ply which are pinched between the cross-cut device and a drive roller of said film feed mechanism. The method of the present invention also preferably comprises using a common drive source to both drive said drive roller and move said cross-cut device. The foam mix input is initiated essentially simultaneously with cross-cut seal formation and without a reversing of the two plies of film earlier fed to said feed mechanism. Also, feeding of said first and second plies includes feeding with said feed mechanism which includes a single drive roller which supplies all driving force with respect to the two plies of film. Preferably, the feeding step includes pinching said first and second ply between said single supply roller and a pair of spaced driven rollers, and said method further comprises feeding a foam mix within a foam reception clearance space between the two plies that lies between said driven rollers at the level of said drive roller.
In a preferred method of forming a bag, the driving of said drive roller and shifting of said cross-cut device is conducted with said motor while said motor is received within a cavity of said drive roller. Under this method, the feed mechanism includes a drive roller and a pair of drive roller in driving engagement with said driven rollers and said film material is passed between said drive roller and driven rollers and said motor drives a drive shaft connected with said drive roller and said motor includes a housing and is a reversible motor; and said feed mechanism includes a one-way rotation device; and said drive roller drives the film material while rotating in a first direction and said one-way rotation device precludes free rotation of said drive roller in an opposite direction to said first direction when said motor is reversed in driving direction and this precluding of said drive roller rotation causes a preventing of rotation of the drive shaft of the motor and a consequential rotation of said motor housing as well as a driving of a transmission system which is connected with said cross-cut bar to implement said shifting of said cross-cut bar. The method further comprises returning the motor to a first drive direction mode and wherein upon return thereto said cross-cut bar is rotated away from a cross-cut formation location to a stand-by state prior to drive roller movement and said rotation of said cross-cut bar to said stand-by state causes a separation of a prior formed bag from a currently being formed bag along a cross-cut seal formed by said cross-cut device.